Beyond3D Forum

FoxMcCloud · 14-Jul-2010, 17:23

An app I'm working on has entered the polishing stage, and one of our goals is to cut down startup time to less than 700 msec, but OpenGL is causing us to hit a glass ceiling due to context creation times - fastest I can get context creation (2.x) on Windows (7, x64 if that matters) is 425 msec. First of all, is this normal or am I doing something drastically wrong? And if it *IS* normal, don't you guys think it's a HUGE amount of time? My dev machine (where those results are from, warm startup) is a Core 2 quad 2.0 with a GTX260M 1 GB. Sampling leads me to believe that ChoosePixelFormat is where the most time is being spent, along with a mysterious wglNumHardwareFormats (Google has no results for the latter).

Any tips on reducing the context creation time? Am I really hitting the ceiling there?

Humus · 20-Jul-2010, 21:49

If ChoosePixelFormat() is taking a lot of time you could try creating your own mode enumeration function and select the best match with more simple logic instead of the rather complex and highly undocumented rules that ChoosePixelFormat() uses.

ERP · 20-Jul-2010, 23:24

My bet would be on the actual mode enumeration.
It can be a lot of combinations when you count all the resolutions x all the possible refresh rates x with Z without Z etc etc.

FoxMcCloud · 21-Jul-2010, 16:19

Humus, I'm interested in bypassing ChoosePixelFormat(), but the MSDN docs are very limited. Where should I go for resources on how to do this?

14-Jul-2010, 17:23	#1
FoxMcCloud Junior Member Join Date: Dec 2008 Posts: 32	OpenGL context creation time on Win32 An app I'm working on has entered the polishing stage, and one of our goals is to cut down startup time to less than 700 msec, but OpenGL is causing us to hit a glass ceiling due to context creation times - fastest I can get context creation (2.x) on Windows (7, x64 if that matters) is 425 msec. First of all, is this normal or am I doing something drastically wrong? And if it IS normal, don't you guys think it's a HUGE amount of time? My dev machine (where those results are from, warm startup) is a Core 2 quad 2.0 with a GTX260M 1 GB. Sampling leads me to believe that ChoosePixelFormat is where the most time is being spent, along with a mysterious wglNumHardwareFormats (Google has no results for the latter). Any tips on reducing the context creation time? Am I really hitting the ceiling there?

20-Jul-2010, 21:49	#2
Humus Crazy coder Join Date: Feb 2002 Location: Stockholm, Sweden Posts: 3,140	If ChoosePixelFormat() is taking a lot of time you could try creating your own mode enumeration function and select the best match with more simple logic instead of the rather complex and highly undocumented rules that ChoosePixelFormat() uses. __________________ [ Visit my site ] I speak for myself and only myself.

20-Jul-2010, 23:24	#3
ERP Moderator Join Date: Feb 2002 Location: Redmond, WA Posts: 2,284	My bet would be on the actual mode enumeration. It can be a lot of combinations when you count all the resolutions x all the possible refresh rates x with Z without Z etc etc. __________________ My "exciting" blog

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21-Jul-2010, 16:19	#4
FoxMcCloud Junior Member Join Date: Dec 2008 Posts: 32	Humus, I'm interested in bypassing ChoosePixelFormat(), but the MSDN docs are very limited. Where should I go for resources on how to do this?

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